People of Saudi Arabia celebrate National Day on September 23. This holiday marks the day of unification of the regions of Saudi Arabia in 1932.

The year of 1744 may be considered to be the birth of Saudi Arabia. Muhammad ibn Abd al-Wahhab, a preacher and a scholar and Muhammad bin Saud, emir of the city of Ad-Diriyyah, founded the House of Saud, the present-day ruling dynasty in Saudi Arabia.

The first Saudi state existed till 1817, when it was defeated by the Ottoman sultan. The second Saudi state was founded in 1824, but in 1891 it was defeated by the enemies of the House of Saud.

Unification of Saudi Arabia was started by Ibn Saud in 1902, when he took over Riyadh. By 1912 he took over the entire region of Nejd and captured Rashidi with the support of the British troops. In 1925 he conquered Heijaz, that is location of the Muslim holy cities of Mecca and Medina.

The conquered territory was named the Kingdom of Nejd and Hejaz and it existed from 1927 till 1932, when it consolidated with Al-Hasa and Qatif into the Kingdom of Saudi Arabia. Anniversary of the unification of the third Saudi state is a national holiday in Saudi Arabia.